This update for shim fixes the following issues :

This update addresses the 'BootHole' security issue (master CVE CVE-2020-10713), by disallowing binaries signed by the previous SUSE UEFI signing key from booting.

This update should only be installed after updates of grub2, the Linux kernel and (if used) Xen from July / August 2020 are applied.

Changes :

Use vendor-dbx to block old SUSE/openSUSE signkeys (bsc#1168994)

Add dbx-cert.tar.xz which contains the certificates to block and a script, generate-vendor-dbx.sh, to generate vendor-dbx.bin

Add vendor-dbx.bin as the vendor dbx to block unwanted keys

Update the path to grub-tpm.efi in shim-install (bsc#1174320)

Only check EFI variable copying when Secure Boot is enabled (bsc#1173411)

Use the full path of efibootmgr to avoid errors when invoking shim-install from packagekitd (bsc#1168104)

shim-install: add check for btrfs is used as root file system to enable relative path lookup for file. (bsc#1153953)

shim-install: install MokManager to \EFI\boot to process the pending MOK request (bsc#1175626, bsc#1175656)

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote NewStart CGSL host, running version CORE 5.04 / MAIN 5.04, has fwupdate packages installed that are affected by a vulnerability:

  - A flaw was found in grub2, prior to version 2.06. An attacker may use the GRUB 2 flaw to hijack and tamper     the GRUB verification process. This flaw also allows the bypass of Secure Boot protections. In order to     load an untrusted or modified kernel, an attacker would first need to establish access to the system such     as gaining physical access, obtain the ability to alter a pxe-boot network, or have remote access to a     networked system with root access. With this access, an attacker could then craft a string to cause a     buffer overflow by injecting a malicious payload that leads to arbitrary code execution within GRUB. The     highest threat from this vulnerability is to data confidentiality and integrity as well as system     availability. (CVE-2020-10713)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

According to the versions of the grub2 packages installed, the EulerOS Virtualization installation on the remote host is affected by the following vulnerabilities :

  - A flaw was found in grub2, prior to version 2.06. An     attacker may use the GRUB 2 flaw to hijack and tamper     the GRUB verification process. This flaw also allows     the bypass of Secure Boot protections. In order to load     an untrusted or modified kernel, an attacker would     first need to establish access to the system such as     gaining physical access, obtain the ability to alter a     pxe-boot network, or have remote access to a networked     system with root access. With this access, an attacker     could then craft a string to cause a buffer overflow by     injecting a malicious payload that leads to arbitrary     code execution within GRUB. The highest threat from     this vulnerability is to data confidentiality and     integrity as well as system     availability.(CVE-2020-10713)

  - Integer overflows were discovered in the functions     grub_cmd_initrd and grub_initrd_init in the efilinux     component of GRUB2, as shipped in Debian, Red Hat, and     Ubuntu (the functionality is not included in GRUB2     upstream), leading to a heap-based buffer overflow.
    These could be triggered by an extremely large number     of arguments to the initrd command on 32-bit     architectures, or a crafted filesystem with very large     files on any architecture. An attacker could use this     to execute arbitrary code and bypass UEFI Secure Boot     restrictions. This issue affects GRUB2 version 2.04 and     prior versions.(CVE-2020-15707)

  - GRUB2 contains a race condition in     grub_script_function_create() leading to a     use-after-free vulnerability which can be triggered by     redefining a function whilst the same function is     already executing, leading to arbitrary code execution     and secure boot restriction bypass. This issue affects     GRUB2 version 2.04 and prior versions.(CVE-2020-15706)

  - There is an issue with grub2 before version 2.06 while     handling symlink on ext filesystems. A filesystem     containing a symbolic link with an inode size of     UINT32_MAX causes an arithmetic overflow leading to a     zero-sized memory allocation with subsequent heap-based     buffer overflow.(CVE-2020-14311)

  - There is an issue on grub2 before version 2.06 at     function read_section_as_string(). It expects a font     name to be at max UINT32_MAX - 1 length in bytes but it     doesn't verify it before proceed with buffer allocation     to read the value from the font value. An attacker may     leverage that by crafting a malicious font file which     has a name with UINT32_MAX, leading to     read_section_as_string() to an arithmetic overflow,     zero-sized allocation and further heap-based buffer     overflow.(CVE-2020-14310)

  - There's an issue with grub2 in all versions before 2.06     when handling squashfs filesystems containing a     symbolic link with name length of UINT32 bytes in size.
    The name size leads to an arithmetic overflow leading     to a zero-size allocation further causing a heap-based     buffer overflow with attacker controlled     data.(CVE-2020-14309)

  - In grub2 versions before 2.06 the grub memory allocator     doesn't check for possible arithmetic overflows on the     requested allocation size. This leads the function to     return invalid memory allocations which can be further     used to cause possible integrity, confidentiality and     availability impacts during the boot     process.(CVE-2020-14308)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote SUSE Linux SLES11 host has a package installed that is affected by a vulnerability as referenced in the SUSE- SU-2020:14490-1 advisory.

  - A flaw was found in grub2, prior to version 2.06. An attacker may use the GRUB 2 flaw to hijack and tamper     the GRUB verification process. This flaw also allows the bypass of Secure Boot protections. In order to     load an untrusted or modified kernel, an attacker would first need to establish access to the system such     as gaining physical access, obtain the ability to alter a pxe-boot network, or have remote access to a     networked system with root access. With this access, an attacker could then craft a string to cause a     buffer overflow by injecting a malicious payload that leads to arbitrary code execution within GRUB. The     highest threat from this vulnerability is to data confidentiality and integrity as well as system     availability. (CVE-2020-10713)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES11 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2020:14440-1 advisory.

  - A flaw was found in grub2, prior to version 2.06. An attacker may use the GRUB 2 flaw to hijack and tamper     the GRUB verification process. This flaw also allows the bypass of Secure Boot protections. In order to     load an untrusted or modified kernel, an attacker would first need to establish access to the system such     as gaining physical access, obtain the ability to alter a pxe-boot network, or have remote access to a     networked system with root access. With this access, an attacker could then craft a string to cause a     buffer overflow by injecting a malicious payload that leads to arbitrary code execution within GRUB. The     highest threat from this vulnerability is to data confidentiality and integrity as well as system     availability. (CVE-2020-10713)

  - In grub2 versions before 2.06 the grub memory allocator doesn't check for possible arithmetic overflows on     the requested allocation size. This leads the function to return invalid memory allocations which can be     further used to cause possible integrity, confidentiality and availability impacts during the boot     process. (CVE-2020-14308)

  - There's an issue with grub2 in all versions before 2.06 when handling squashfs filesystems containing a     symbolic link with name length of UINT32 bytes in size. The name size leads to an arithmetic overflow     leading to a zero-size allocation further causing a heap-based buffer overflow with attacker controlled     data. (CVE-2020-14309)

  - There is an issue on grub2 before version 2.06 at function read_section_as_string(). It expects a font     name to be at max UINT32_MAX - 1 length in bytes but it doesn't verify it before proceed with buffer     allocation to read the value from the font value. An attacker may leverage that by crafting a malicious     font file which has a name with UINT32_MAX, leading to read_section_as_string() to an arithmetic overflow,     zero-sized allocation and further heap-based buffer overflow. (CVE-2020-14310)

  - There is an issue with grub2 before version 2.06 while handling symlink on ext filesystems. A filesystem     containing a symbolic link with an inode size of UINT32_MAX causes an arithmetic overflow leading to a     zero-sized memory allocation with subsequent heap-based buffer overflow. (CVE-2020-14311)

  - GRUB2 contains a race condition in grub_script_function_create() leading to a use-after-free vulnerability     which can be triggered by redefining a function whilst the same function is already executing, leading to     arbitrary code execution and secure boot restriction bypass. This issue affects GRUB2 version 2.04 and     prior versions. (CVE-2020-15706)

  - Integer overflows were discovered in the functions grub_cmd_initrd and grub_initrd_init in the efilinux     component of GRUB2, as shipped in Debian, Red Hat, and Ubuntu (the functionality is not included in GRUB2     upstream), leading to a heap-based buffer overflow. These could be triggered by an extremely large number     of arguments to the initrd command on 32-bit architectures, or a crafted filesystem with very large files     on any architecture. An attacker could use this to execute arbitrary code and bypass UEFI Secure Boot     restrictions. This issue affects GRUB2 version 2.04 and prior versions. (CVE-2020-15707)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Published	Updated	Severity
143746	SUSE SLED15 / SLES15 Security Update : shim (SUSE-SU-2020:2629-1)	Nessus	SuSE Local Security Checks	12/9/2020	12/12/2023	high
147391	NewStart CGSL CORE 5.04 / MAIN 5.04 : fwupdate Vulnerability (NS-SA-2021-0007)	Nessus	NewStart CGSL Local Security Checks	3/10/2021	12/5/2022	high
147445	EulerOS Virtualization 2.9.1 : grub2 (EulerOS-SA-2021-1601)	Nessus	Huawei Local Security Checks	3/10/2021	1/11/2024	high
150569	SUSE SLES11 Security Update : shim (SUSE-SU-2020:14490-1)	Nessus	SuSE Local Security Checks	6/10/2021	12/5/2022	high
150632	SUSE SLES11 Security Update : grub2 (SUSE-SU-2020:14440-1)	Nessus	SuSE Local Security Checks	6/10/2021	12/26/2023	high

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